Improve Type Safety and OpenAPI Schema for PDF API Controllers and Models (#3470)

# Description of Changes

- **What was changed**  
- Updated controller methods to use strongly‐typed primitives (`int`,
`long`, `boolean`) instead of `String` for numeric and boolean
parameters, eliminating calls to `Integer.parseInt`/`Long.parseLong` and
improving null‐safety (`Boolean.TRUE.equals(...)`).
- Enhanced all API request model classes with richer Swagger/OpenAPI
annotations: added `requiredMode`, `defaultValue`, `allowableValues`,
`format`, `pattern`, and tightened schema descriptions for all fields.
- Refactored HTML form templates for “Remove Blank Pages” to include
`min`, `max`, and `step` attributes on numeric inputs, matching the
updated validation rules.

- **Why the change was made**  
- **Type safety & robustness**: Shifting from `String` to native types
prevents runtime parsing errors, simplifies controller logic, and makes
default values explicit.
- **Better API documentation & validation**: Enriching the Swagger
annotations ensures generated docs accurately reflect required fields,
default values, and permitted ranges, which improves client code
generation and developer experience.
- **Consistency across codebase**: Aligning all request models and
controllers enforces a uniform coding style and reduces bugs.

#3406

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

src/main/java/stirling/software/SPDF/controller/api/AnalysisController.java

@@ -59,7 +59,8 @@ public class AnalysisController {
             description = "Returns title, author, subject, etc. Input:PDF Output:JSON Type:SISO")
     public Map<String, String> getDocumentProperties(@ModelAttribute PDFFile file)
             throws IOException {
-        // Load the document in read-only mode to prevent modifications and ensure the integrity of the original file.
+        // Load the document in read-only mode to prevent modifications and ensure the integrity of
+        // the original file.
         try (PDDocument document = pdfDocumentFactory.load(file.getFileInput(), true)) {
             PDDocumentInformation info = document.getDocumentInformation();
             Map<String, String> properties = new HashMap<>();
@@ -180,7 +181,8 @@ public class AnalysisController {
 
                 // Get permissions
                 Map<String, Boolean> permissions = new HashMap<>();
-                permissions.put("preventPrinting", !document.getCurrentAccessPermission().canPrint());
+                permissions.put(
+                        "preventPrinting", !document.getCurrentAccessPermission().canPrint());
                 permissions.put(
                         "preventModify", !document.getCurrentAccessPermission().canModify());
                 permissions.put(

src/main/java/stirling/software/SPDF/controller/api/CropController.java

@@ -39,8 +39,8 @@ public class CropController {
             description =
                     "This operation takes an input PDF file and crops it according to the given"
                             + " coordinates. Input:PDF Output:PDF Type:SISO")
-    public ResponseEntity<byte[]> cropPdf(@ModelAttribute CropPdfForm form) throws IOException {
-        PDDocument sourceDocument = pdfDocumentFactory.load(form);
+    public ResponseEntity<byte[]> cropPdf(@ModelAttribute CropPdfForm request) throws IOException {
+        PDDocument sourceDocument = pdfDocumentFactory.load(request);
 
         PDDocument newDocument =
                 pdfDocumentFactory.createNewDocumentBasedOnOldDocument(sourceDocument);
@@ -64,7 +64,8 @@ public class CropController {
             contentStream.saveGraphicsState();
 
             // Define the crop area
-            contentStream.addRect(form.getX(), form.getY(), form.getWidth(), form.getHeight());
+            contentStream.addRect(
+                    request.getX(), request.getY(), request.getWidth(), request.getHeight());
             contentStream.clip();
 
             // Draw the entire formXObject
@@ -76,7 +77,11 @@ public class CropController {
 
             // Now, set the new page's media box to the cropped size
             newPage.setMediaBox(
-                    new PDRectangle(form.getX(), form.getY(), form.getWidth(), form.getHeight()));
+                    new PDRectangle(
+                            request.getX(),
+                            request.getY(),
+                            request.getWidth(),
+                            request.getHeight()));
         }
 
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -87,7 +92,7 @@ public class CropController {
         byte[] pdfContent = baos.toByteArray();
         return WebResponseUtils.bytesToWebResponse(
                 pdfContent,
-                form.getFileInput().getOriginalFilename().replaceFirst("[.][^.]+$", "")
+                request.getFileInput().getOriginalFilename().replaceFirst("[.][^.]+$", "")
                         + "_cropped.pdf");
     }
 }

src/main/java/stirling/software/SPDF/controller/api/EmailController.java

@@ -8,6 +8,7 @@ import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import jakarta.mail.MessagingException;
@@ -41,7 +42,13 @@ public class EmailController {
      * @return ResponseEntity with success or error message.
      */
     @PostMapping(consumes = "multipart/form-data", value = "/send-email")
+    @Operation(
+            summary = "Send an email with an attachment",
+            description =
+                    "This endpoint sends an email with an attachment. Input:PDF"
+                            + " Output:Success/Failure Type:MISO")
     public ResponseEntity<String> sendEmailWithAttachment(@Valid @ModelAttribute Email email) {
+        log.info("Sending email to: {}", email.toString());
         try {
             // Calls the service to send the email with attachment
             emailService.sendEmailWithAttachment(email);

src/main/java/stirling/software/SPDF/controller/api/MergeController.java

@@ -117,20 +117,20 @@ public class MergeController {
                     "This endpoint merges multiple PDF files into a single PDF file. The merged"
                             + " file will contain all pages from the input files in the order they were"
                             + " provided. Input:PDF Output:PDF Type:MISO")
-    public ResponseEntity<byte[]> mergePdfs(@ModelAttribute MergePdfsRequest form)
+    public ResponseEntity<byte[]> mergePdfs(@ModelAttribute MergePdfsRequest request)
             throws IOException {
         List<File> filesToDelete = new ArrayList<>(); // List of temporary files to delete
         File mergedTempFile = null;
         PDDocument mergedDocument = null;
 
-        boolean removeCertSign = form.isRemoveCertSign();
+        boolean removeCertSign = Boolean.TRUE.equals(request.getRemoveCertSign());
 
         try {
-            MultipartFile[] files = form.getFileInput();
+            MultipartFile[] files = request.getFileInput();
             Arrays.sort(
                     files,
                     getSortComparator(
-                            form.getSortType())); // Sort files based on the given sort type
+                            request.getSortType())); // Sort files based on the given sort type
 
             PDFMergerUtility mergerUtility = new PDFMergerUtility();
             long totalSize = 0;

src/main/java/stirling/software/SPDF/controller/api/MultiPageLayoutController.java

@@ -47,7 +47,7 @@ public class MultiPageLayoutController {
 
         int pagesPerSheet = request.getPagesPerSheet();
         MultipartFile file = request.getFileInput();
-        boolean addBorder = request.isAddBorder();
+        boolean addBorder = Boolean.TRUE.equals(request.getAddBorder());
 
         if (pagesPerSheet != 2
                 && pagesPerSheet != 3

src/main/java/stirling/software/SPDF/controller/api/SplitPdfByChaptersController.java

@@ -127,7 +127,7 @@ public class SplitPdfByChaptersController {
         Path zipFile = null;
 
         try {
-            boolean includeMetadata = request.getIncludeMetadata();
+            boolean includeMetadata = Boolean.TRUE.equals(request.getIncludeMetadata());
             Integer bookmarkLevel =
                     request.getBookmarkLevel(); // levels start from 0 (top most bookmarks)
             if (bookmarkLevel < 0) {
@@ -161,7 +161,7 @@ public class SplitPdfByChaptersController {
                         .body("Unable to extract outline items".getBytes());
             }
 
-            boolean allowDuplicates = request.getAllowDuplicates();
+            boolean allowDuplicates = Boolean.TRUE.equals(request.getAllowDuplicates());
             if (!allowDuplicates) {
                 /*
                 duplicates are generated when multiple bookmarks correspond to the same page,

src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySectionsController.java

@@ -60,7 +60,7 @@ public class SplitPdfBySectionsController {
         // Process the PDF based on split parameters
         int horiz = request.getHorizontalDivisions() + 1;
         int verti = request.getVerticalDivisions() + 1;
-        boolean merge = request.isMerge();
+        boolean merge = Boolean.TRUE.equals(request.getMerge());
         List<PDDocument> splitDocuments = splitPdfPages(sourceDocument, verti, horiz);
 
         String filename =

src/main/java/stirling/software/SPDF/controller/api/converters/ConvertImgPDFController.java

@@ -58,7 +58,7 @@ public class ConvertImgPDFController {
         String imageFormat = request.getImageFormat();
         String singleOrMultiple = request.getSingleOrMultiple();
         String colorType = request.getColorType();
-        String dpi = request.getDpi();
+        int dpi = request.getDpi();
         String pageNumbers = request.getPageNumbers();
         Path tempFile = null;
         Path tempOutputDir = null;
@@ -94,7 +94,7 @@ public class ConvertImgPDFController {
                                     : imageFormat.toUpperCase(),
                             colorTypeResult,
                             singleImage,
-                            Integer.valueOf(dpi),
+                            dpi,
                             filename);
             if (result == null || result.length == 0) {
                 log.error("resultant bytes for {} is null, error converting ", filename);
@@ -132,7 +132,7 @@ public class ConvertImgPDFController {
                     command.add(tempOutputDir.toString());
                 }
                 command.add("--dpi");
-                command.add(dpi);
+                command.add(String.valueOf(dpi));
                 ProcessExecutorResult resultProcess =
                         ProcessExecutor.getInstance(ProcessExecutor.Processes.PYTHON_OPENCV)
                                 .runCommandWithOutputHandling(command);
@@ -213,7 +213,7 @@ public class ConvertImgPDFController {
         MultipartFile[] file = request.getFileInput();
         String fitOption = request.getFitOption();
         String colorType = request.getColorType();
-        boolean autoRotate = request.isAutoRotate();
+        boolean autoRotate = Boolean.TRUE.equals(request.getAutoRotate());
         // Handle Null entries for formdata
         if (colorType == null || colorType.isBlank()) {
             colorType = "color";

src/main/java/stirling/software/SPDF/controller/api/converters/ConvertMarkdownToPdf.java

@@ -47,9 +47,8 @@ public class ConvertMarkdownToPdf {
             description =
                     "This endpoint takes a Markdown file input, converts it to HTML, and then to"
                             + " PDF format. Input:MARKDOWN Output:PDF Type:SISO")
-    public ResponseEntity<byte[]> markdownToPdf(@ModelAttribute GeneralFile request)
-            throws Exception {
-        MultipartFile fileInput = request.getFileInput();
+    public ResponseEntity<byte[]> markdownToPdf(@ModelAttribute GeneralFile generalFile) throws Exception {
+        MultipartFile fileInput = generalFile.getFileInput();
 
         if (fileInput == null) {
             throw new IllegalArgumentException("Please provide a Markdown file for conversion.");

src/main/java/stirling/software/SPDF/controller/api/converters/ConvertOfficeController.java

@@ -90,9 +90,9 @@ public class ConvertOfficeController {
             description =
                     "This endpoint converts a given file to a PDF using LibreOffice API  Input:ANY"
                             + " Output:PDF Type:SISO")
-    public ResponseEntity<byte[]> processFileToPDF(@ModelAttribute GeneralFile request)
+    public ResponseEntity<byte[]> processFileToPDF(@ModelAttribute GeneralFile generalFile)
             throws Exception {
-        MultipartFile inputFile = request.getFileInput();
+        MultipartFile inputFile = generalFile.getFileInput();
         // unused but can start server instance if startup time is to long
         // LibreOfficeListener.getInstance().start();
         File file = null;

src/main/java/stirling/software/SPDF/controller/api/converters/ConvertPDFToHtml.java

@@ -23,9 +23,8 @@ public class ConvertPDFToHtml {
             summary = "Convert PDF to HTML",
             description =
                     "This endpoint converts a PDF file to HTML format. Input:PDF Output:HTML Type:SISO")
-    public ResponseEntity<byte[]> processPdfToHTML(@ModelAttribute PDFFile request)
-            throws Exception {
-        MultipartFile inputFile = request.getFileInput();
+    public ResponseEntity<byte[]> processPdfToHTML(@ModelAttribute PDFFile file) throws Exception {
+        MultipartFile inputFile = file.getFileInput();
         PDFToFile pdfToFile = new PDFToFile();
         return pdfToFile.processPdfToHtml(inputFile);
     }

src/main/java/stirling/software/SPDF/controller/api/converters/ConvertPDFToOffice.java

@@ -97,9 +97,8 @@ public class ConvertPDFToOffice {
             description =
                     "This endpoint converts a PDF file to an XML file. Input:PDF Output:XML"
                             + " Type:SISO")
-    public ResponseEntity<byte[]> processPdfToXML(@ModelAttribute PDFFile request)
-            throws Exception {
-        MultipartFile inputFile = request.getFileInput();
+    public ResponseEntity<byte[]> processPdfToXML(@ModelAttribute PDFFile file) throws Exception {
+        MultipartFile inputFile = file.getFileInput();
 
         PDFToFile pdfToFile = new PDFToFile();
         return pdfToFile.processPdfToOfficeFormat(inputFile, "xml", "writer_pdf_import");

src/main/java/stirling/software/SPDF/controller/api/converters/ExtractCSVController.java

@@ -52,12 +52,12 @@ public class ExtractCSVController {
             description =
                     "This operation takes an input PDF file and returns CSV file of whole page."
                             + " Input:PDF Output:CSV Type:SISO")
-    public ResponseEntity<?> pdfToCsv(@ModelAttribute PDFWithPageNums form) throws Exception {
-        String baseName = getBaseName(form.getFileInput().getOriginalFilename());
+    public ResponseEntity<?> pdfToCsv(@ModelAttribute PDFWithPageNums request) throws Exception {
+        String baseName = getBaseName(request.getFileInput().getOriginalFilename());
         List<CsvEntry> csvEntries = new ArrayList<>();
 
-        try (PDDocument document = pdfDocumentFactory.load(form)) {
-            List<Integer> pages = form.getPageNumbersList(document, true);
+        try (PDDocument document = pdfDocumentFactory.load(request)) {
+            List<Integer> pages = request.getPageNumbersList(document, true);
             SpreadsheetExtractionAlgorithm sea = new SpreadsheetExtractionAlgorithm();
             CSVFormat format =
                     CSVFormat.EXCEL.builder().setEscape('"').setQuoteMode(QuoteMode.ALL).build();

src/main/java/stirling/software/SPDF/controller/api/filters/FilterController.java

@@ -77,7 +77,7 @@ public class FilterController {
     public ResponseEntity<byte[]> pageCount(@ModelAttribute PDFComparisonAndCount request)
             throws IOException, InterruptedException {
         MultipartFile inputFile = request.getFileInput();
-        String pageCount = request.getPageCount();
+        int pageCount = request.getPageCount();
         String comparator = request.getComparator();
         // Load the PDF
         PDDocument document = pdfDocumentFactory.load(inputFile);
@@ -87,13 +87,13 @@ public class FilterController {
         // Perform the comparison
         switch (comparator) {
             case "Greater":
-                valid = actualPageCount > Integer.parseInt(pageCount);
+                valid = actualPageCount > pageCount;
                 break;
             case "Equal":
-                valid = actualPageCount == Integer.parseInt(pageCount);
+                valid = actualPageCount == pageCount;
                 break;
             case "Less":
-                valid = actualPageCount < Integer.parseInt(pageCount);
+                valid = actualPageCount < pageCount;
                 break;
             default:
                 throw new IllegalArgumentException("Invalid comparator: " + comparator);
@@ -153,7 +153,7 @@ public class FilterController {
     public ResponseEntity<byte[]> fileSize(@ModelAttribute FileSizeRequest request)
             throws IOException, InterruptedException {
         MultipartFile inputFile = request.getFileInput();
-        String fileSize = request.getFileSize();
+        long fileSize = request.getFileSize();
         String comparator = request.getComparator();
 
         // Get the file size
@@ -163,13 +163,13 @@ public class FilterController {
         // Perform the comparison
         switch (comparator) {
             case "Greater":
-                valid = actualFileSize > Long.parseLong(fileSize);
+                valid = actualFileSize > fileSize;
                 break;
             case "Equal":
-                valid = actualFileSize == Long.parseLong(fileSize);
+                valid = actualFileSize == fileSize;
                 break;
             case "Less":
-                valid = actualFileSize < Long.parseLong(fileSize);
+                valid = actualFileSize < fileSize;
                 break;
             default:
                 throw new IllegalArgumentException("Invalid comparator: " + comparator);

src/main/java/stirling/software/SPDF/controller/api/misc/AutoRenameController.java

@@ -47,7 +47,7 @@ public class AutoRenameController {
     public ResponseEntity<byte[]> extractHeader(@ModelAttribute ExtractHeaderRequest request)
             throws Exception {
         MultipartFile file = request.getFileInput();
-        Boolean useFirstTextAsFallback = request.isUseFirstTextAsFallback();
+        boolean useFirstTextAsFallback = Boolean.TRUE.equals(request.getUseFirstTextAsFallback());
 
         PDDocument document = pdfDocumentFactory.load(file);
         PDFTextStripper reader =

src/main/java/stirling/software/SPDF/controller/api/misc/AutoSplitPdfController.java

@@ -113,7 +113,7 @@ public class AutoSplitPdfController {
     public ResponseEntity<byte[]> autoSplitPdf(@ModelAttribute AutoSplitPdfRequest request)
             throws IOException {
         MultipartFile file = request.getFileInput();
-        boolean duplexMode = request.isDuplexMode();
+        boolean duplexMode = Boolean.TRUE.equals(request.getDuplexMode());
 
         PDDocument document = null;
         List<PDDocument> splitDocuments = new ArrayList<>();

src/main/java/stirling/software/SPDF/controller/api/misc/ExtractImageScansController.java

@@ -18,14 +18,13 @@ import org.apache.pdfbox.pdmodel.PDDocument;
 import org.apache.pdfbox.rendering.PDFRenderer;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.multipart.MultipartFile;
 
 import io.swagger.v3.oas.annotations.Operation;
-import io.swagger.v3.oas.annotations.media.Content;
-import io.swagger.v3.oas.annotations.media.Schema;
-import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import lombok.RequiredArgsConstructor;
@@ -58,24 +57,11 @@ public class ExtractImageScansController {
                             + " minimum contour area, and border size. Input:PDF Output:IMAGE/ZIP"
                             + " Type:SIMO")
     public ResponseEntity<byte[]> extractImageScans(
-            @RequestBody(
-                            description = "Form data containing file and extraction parameters",
-                            required = true,
-                            content =
-                                    @Content(
-                                            mediaType = "multipart/form-data",
-                                            schema =
-                                                    @Schema(
-                                                            implementation =
-                                                                    ExtractImageScansRequest
-                                                                            .class) // This should
-                                            // represent
-                                            // your form's
-                                            // structure
-                                            ))
-                    ExtractImageScansRequest form)
+            @ModelAttribute ExtractImageScansRequest request)
             throws IOException, InterruptedException {
-        String fileName = form.getFileInput().getOriginalFilename();
+        MultipartFile inputFile = request.getFileInput();
+
+        String fileName = inputFile.getOriginalFilename();
         String extension = fileName.substring(fileName.lastIndexOf(".") + 1);
 
         List<String> images = new ArrayList<>();
@@ -94,7 +80,7 @@ public class ExtractImageScansController {
             // Check if input file is a PDF
             if ("pdf".equalsIgnoreCase(extension)) {
                 // Load PDF document
-                try (PDDocument document = pdfDocumentFactory.load(form.getFileInput())) {
+                try (PDDocument document = pdfDocumentFactory.load(inputFile)) {
                     PDFRenderer pdfRenderer = new PDFRenderer(document);
                     pdfRenderer.setSubsamplingAllowed(true);
                     int pageCount = document.getNumberOfPages();
@@ -116,7 +102,7 @@ public class ExtractImageScansController {
                 }
             } else {
                 tempInputFile = Files.createTempFile("input_", "." + extension);
-                form.getFileInput().transferTo(tempInputFile);
+                inputFile.transferTo(tempInputFile);
                 // Add input file path to images list
                 images.add(tempInputFile.toString());
             }
@@ -136,15 +122,15 @@ public class ExtractImageScansController {
                                         images.get(i),
                                         tempDir.toString(),
                                         "--angle_threshold",
-                                        String.valueOf(form.getAngleThreshold()),
+                                        String.valueOf(request.getAngleThreshold()),
                                         "--tolerance",
-                                        String.valueOf(form.getTolerance()),
+                                        String.valueOf(request.getTolerance()),
                                         "--min_area",
-                                        String.valueOf(form.getMinArea()),
+                                        String.valueOf(request.getMinArea()),
                                         "--min_contour_area",
-                                        String.valueOf(form.getMinContourArea()),
+                                        String.valueOf(request.getMinContourArea()),
                                         "--border_size",
-                                        String.valueOf(form.getBorderSize())));
+                                        String.valueOf(request.getBorderSize())));
 
                 // Run CLI command
                 ProcessExecutorResult returnCode =

src/main/java/stirling/software/SPDF/controller/api/misc/ExtractImagesController.java

@@ -64,7 +64,7 @@ public class ExtractImagesController {
             throws IOException, InterruptedException, ExecutionException {
         MultipartFile file = request.getFileInput();
         String format = request.getFormat();
-        boolean allowDuplicates = request.isAllowDuplicates();
+        boolean allowDuplicates = Boolean.TRUE.equals(request.getAllowDuplicates());
         PDDocument document = pdfDocumentFactory.load(file);
 
         // Determine if multithreading should be used based on PDF size or number of pages

src/main/java/stirling/software/SPDF/controller/api/misc/MetadataController.java

@@ -65,7 +65,7 @@ public class MetadataController {
         MultipartFile pdfFile = request.getFileInput();
 
         // Extract metadata information
-        Boolean deleteAll = request.isDeleteAll();
+        boolean deleteAll = Boolean.TRUE.equals(request.getDeleteAll());
         String author = request.getAuthor();
         String creationDate = request.getCreationDate();
         String creator = request.getCreator();

src/main/java/stirling/software/SPDF/controller/api/misc/OverlayImageController.java

@@ -43,7 +43,7 @@ public class OverlayImageController {
         MultipartFile imageFile = request.getImageFile();
         float x = request.getX();
         float y = request.getY();
-        boolean everyPage = request.isEveryPage();
+        boolean everyPage = Boolean.TRUE.equals(request.getEveryPage());
         try {
             byte[] pdfBytes = pdfFile.getBytes();
             byte[] imageBytes = imageFile.getBytes();

src/main/java/stirling/software/SPDF/controller/api/misc/PageNumbersController.java

@@ -49,33 +49,30 @@ public class PageNumbersController {
         MultipartFile file = request.getFileInput();
         String customMargin = request.getCustomMargin();
         int position = request.getPosition();
-        int startingNumber = request.getStartingNumber();
+        int pageNumber = request.getStartingNumber();
         String pagesToNumber = request.getPagesToNumber();
         String customText = request.getCustomText();
-        int pageNumber = startingNumber;
+        float fontSize = request.getFontSize();
+        String fontType = request.getFontType();
+
         PDDocument document = pdfDocumentFactory.load(file);
-        float font_size = request.getFontSize();
-        String font_type = request.getFontType();
         float marginFactor;
         switch (customMargin.toLowerCase()) {
             case "small":
                 marginFactor = 0.02f;
                 break;
-            case "medium":
-                marginFactor = 0.035f;
-                break;
             case "large":
                 marginFactor = 0.05f;
                 break;
             case "x-large":
                 marginFactor = 0.075f;
                 break;
+            case "medium":
             default:
                 marginFactor = 0.035f;
                 break;
         }
 
-        float fontSize = font_size;
         if (pagesToNumber == null || pagesToNumber.isEmpty()) {
             pagesToNumber = "all";
         }
@@ -99,7 +96,7 @@ public class PageNumbersController {
                                             .replaceFirst("[.][^.]+$", ""));
 
             PDType1Font currentFont =
-                    switch (font_type.toLowerCase()) {
+                    switch (fontType.toLowerCase()) {
                         case "courier" -> new PDType1Font(Standard14Fonts.FontName.COURIER);
                         case "times" -> new PDType1Font(Standard14Fonts.FontName.TIMES_ROMAN);
                         default -> new PDType1Font(Standard14Fonts.FontName.HELVETICA);

src/main/java/stirling/software/SPDF/controller/api/misc/RepairController.java

@@ -40,9 +40,9 @@ public class RepairController {
                     "This endpoint repairs a given PDF file by running qpdf command. The PDF is"
                             + " first saved to a temporary location, repaired, read back, and then"
                             + " returned as a response. Input:PDF Output:PDF Type:SISO")
-    public ResponseEntity<byte[]> repairPdf(@ModelAttribute PDFFile request)
+    public ResponseEntity<byte[]> repairPdf(@ModelAttribute PDFFile file)
             throws IOException, InterruptedException {
-        MultipartFile inputFile = request.getFileInput();
+        MultipartFile inputFile = file.getFileInput();
         // Save the uploaded file to a temporary location
         Path tempInputFile = Files.createTempFile("input_", ".pdf");
         byte[] pdfBytes = null;

src/main/java/stirling/software/SPDF/controller/api/misc/ReplaceAndInvertColorController.java

@@ -31,18 +31,18 @@ public class ReplaceAndInvertColorController {
     @Operation(
             summary = "Replace-Invert Color PDF",
             description =
-                    "This endpoint accepts a PDF file and option of invert all colors or replace text and background colors. Input:PDF Output:PDF Type:SISO")
+                    "This endpoint accepts a PDF file and option of invert all colors or replace"
+                            + " text and background colors. Input:PDF Output:PDF Type:SISO")
     public ResponseEntity<InputStreamResource> replaceAndInvertColor(
-            @ModelAttribute ReplaceAndInvertColorRequest replaceAndInvertColorRequest)
-            throws IOException {
+            @ModelAttribute ReplaceAndInvertColorRequest request) throws IOException {
 
         InputStreamResource resource =
                 replaceAndInvertColorService.replaceAndInvertColor(
-                        replaceAndInvertColorRequest.getFileInput(),
-                        replaceAndInvertColorRequest.getReplaceAndInvertOption(),
-                        replaceAndInvertColorRequest.getHighContrastColorCombination(),
-                        replaceAndInvertColorRequest.getBackGroundColor(),
-                        replaceAndInvertColorRequest.getTextColor());
+                        request.getFileInput(),
+                        request.getReplaceAndInvertOption(),
+                        request.getHighContrastColorCombination(),
+                        request.getBackGroundColor(),
+                        request.getTextColor());
 
         // Return the modified PDF as a downloadable file
         return ResponseEntity.ok()

src/main/java/stirling/software/SPDF/controller/api/misc/ShowJavascript.java

@@ -36,8 +36,8 @@ public class ShowJavascript {
     @Operation(
             summary = "Grabs all JS from a PDF and returns a single JS file with all code",
             description = "desc. Input:PDF Output:JS Type:SISO")
-    public ResponseEntity<byte[]> extractHeader(@ModelAttribute PDFFile request) throws Exception {
-        MultipartFile inputFile = request.getFileInput();
+    public ResponseEntity<byte[]> extractHeader(@ModelAttribute PDFFile file) throws Exception {
+        MultipartFile inputFile = file.getFileInput();
         String script = "";
 
         try (PDDocument document = pdfDocumentFactory.load(inputFile)) {

src/main/java/stirling/software/SPDF/controller/api/security/PasswordController.java

@@ -63,14 +63,16 @@ public class PasswordController {
         String ownerPassword = request.getOwnerPassword();
         String password = request.getPassword();
         int keyLength = request.getKeyLength();
-        boolean preventAssembly = request.isPreventAssembly();
-        boolean preventExtractContent = request.isPreventExtractContent();
-        boolean preventExtractForAccessibility = request.isPreventExtractForAccessibility();
-        boolean preventFillInForm = request.isPreventFillInForm();
-        boolean preventModify = request.isPreventModify();
-        boolean preventModifyAnnotations = request.isPreventModifyAnnotations();
-        boolean preventPrinting = request.isPreventPrinting();
-        boolean preventPrintingFaithful = request.isPreventPrintingFaithful();
+        boolean preventAssembly = Boolean.TRUE.equals(request.getPreventAssembly());
+        boolean preventExtractContent = Boolean.TRUE.equals(request.getPreventExtractContent());
+        boolean preventExtractForAccessibility =
+                Boolean.TRUE.equals(request.getPreventExtractForAccessibility());
+        boolean preventFillInForm = Boolean.TRUE.equals(request.getPreventFillInForm());
+        boolean preventModify = Boolean.TRUE.equals(request.getPreventModify());
+        boolean preventModifyAnnotations =
+                Boolean.TRUE.equals(request.getPreventModifyAnnotations());
+        boolean preventPrinting = Boolean.TRUE.equals(request.getPreventPrinting());
+        boolean preventPrintingFaithful = Boolean.TRUE.equals(request.getPreventPrintingFaithful());
 
         PDDocument document = pdfDocumentFactory.load(fileInput);
         AccessPermission ap = new AccessPermission();

src/main/java/stirling/software/SPDF/controller/api/security/RedactController.java

@@ -75,7 +75,7 @@ public class RedactController {
         redactPages(request, document, allPages);
         redactAreas(redactionAreas, document, allPages);
 
-        if (request.isConvertPDFToImage()) {
+        if (Boolean.TRUE.equals(request.getConvertPDFToImage())) {
             PDDocument convertedPdf = PdfUtils.convertPdfToPdfImage(document);
             document.close();
             document = convertedPdf;
@@ -180,7 +180,6 @@ public class RedactController {
         }
     }
 
-
     private List<Integer> getPageNumbers(ManualRedactPdfRequest request, int pagesCount) {
         String pageNumbersInput = request.getPageNumbers();
         String[] parsedPageNumbers =
@@ -201,11 +200,11 @@ public class RedactController {
             throws Exception {
         MultipartFile file = request.getFileInput();
         String listOfTextString = request.getListOfText();
-        boolean useRegex = request.isUseRegex();
-        boolean wholeWordSearchBool = request.isWholeWordSearch();
+        boolean useRegex = Boolean.TRUE.equals(request.getUseRegex());
+        boolean wholeWordSearchBool = Boolean.TRUE.equals(request.getWholeWordSearch());
         String colorString = request.getRedactColor();
         float customPadding = request.getCustomPadding();
-        boolean convertPDFToImage = request.isConvertPDFToImage();
+        boolean convertPDFToImage = Boolean.TRUE.equals(request.getConvertPDFToImage());
 
         String[] listOfText = listOfTextString.split("\n");
         PDDocument document = pdfDocumentFactory.load(file);

src/main/java/stirling/software/SPDF/controller/api/security/SanitizeController.java

@@ -46,12 +46,12 @@ public class SanitizeController {
     public ResponseEntity<byte[]> sanitizePDF(@ModelAttribute SanitizePdfRequest request)
             throws IOException {
         MultipartFile inputFile = request.getFileInput();
-        boolean removeJavaScript = request.isRemoveJavaScript();
-        boolean removeEmbeddedFiles = request.isRemoveEmbeddedFiles();
-        boolean removeXMPMetadata = request.isRemoveXMPMetadata();
-        boolean removeMetadata = request.isRemoveMetadata();
-        boolean removeLinks = request.isRemoveLinks();
-        boolean removeFonts = request.isRemoveFonts();
+        boolean removeJavaScript = Boolean.TRUE.equals(request.getRemoveJavaScript());
+        boolean removeEmbeddedFiles = Boolean.TRUE.equals(request.getRemoveEmbeddedFiles());
+        boolean removeXMPMetadata = Boolean.TRUE.equals(request.getRemoveXMPMetadata());
+        boolean removeMetadata = Boolean.TRUE.equals(request.getRemoveMetadata());
+        boolean removeLinks = Boolean.TRUE.equals(request.getRemoveLinks());
+        boolean removeFonts = Boolean.TRUE.equals(request.getRemoveFonts());
 
         PDDocument document = pdfDocumentFactory.load(inputFile, true);
         if (removeJavaScript) {

src/main/java/stirling/software/SPDF/controller/api/security/ValidateSignatureController.java

@@ -1,5 +1,6 @@
 package stirling.software.SPDF.controller.api.security;
 
+import java.beans.PropertyEditorSupport;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.security.cert.CertificateException;
@@ -23,6 +24,8 @@ import org.bouncycastle.cms.jcajce.JcaSimpleSignerInfoVerifierBuilder;
 import org.bouncycastle.util.Store;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.WebDataBinder;
+import org.springframework.web.bind.annotation.InitBinder;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -48,6 +51,18 @@ public class ValidateSignatureController {
     private final CustomPDFDocumentFactory pdfDocumentFactory;
     private final CertificateValidationService certValidationService;
 
+    @InitBinder
+    public void initBinder(WebDataBinder binder) {
+        binder.registerCustomEditor(
+                MultipartFile.class,
+                new PropertyEditorSupport() {
+                    @Override
+                    public void setAsText(String text) throws IllegalArgumentException {
+                        setValue(null);
+                    }
+                });
+    }
+
     @Operation(
             summary = "Validate PDF Digital Signature",
             description =
@@ -58,12 +73,12 @@ public class ValidateSignatureController {
             @ModelAttribute SignatureValidationRequest request) throws IOException {
         List<SignatureValidationResult> results = new ArrayList<>();
         MultipartFile file = request.getFileInput();
+        MultipartFile certFile = request.getCertFile();
 
         // Load custom certificate if provided
         X509Certificate customCert = null;
-        if (request.getCertFile() != null && !request.getCertFile().isEmpty()) {
-            try (ByteArrayInputStream certStream =
-                    new ByteArrayInputStream(request.getCertFile().getBytes())) {
+        if (certFile != null && !certFile.isEmpty()) {
+            try (ByteArrayInputStream certStream = new ByteArrayInputStream(certFile.getBytes())) {
                 CertificateFactory cf = CertificateFactory.getInstance("X.509");
                 customCert = (X509Certificate) cf.generateCertificate(certStream);
             } catch (CertificateException e) {

src/main/java/stirling/software/SPDF/controller/api/security/WatermarkController.java

@@ -2,6 +2,7 @@ package stirling.software.SPDF.controller.api.security;
 
 import java.awt.*;
 import java.awt.image.BufferedImage;
+import java.beans.PropertyEditorSupport;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -24,6 +25,8 @@ import org.apache.pdfbox.pdmodel.graphics.state.PDExtendedGraphicsState;
 import org.apache.pdfbox.util.Matrix;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.WebDataBinder;
+import org.springframework.web.bind.annotation.InitBinder;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -49,6 +52,18 @@ public class WatermarkController {
 
     private final CustomPDFDocumentFactory pdfDocumentFactory;
 
+    @InitBinder
+    public void initBinder(WebDataBinder binder) {
+        binder.registerCustomEditor(
+                MultipartFile.class,
+                new PropertyEditorSupport() {
+                    @Override
+                    public void setAsText(String text) throws IllegalArgumentException {
+                        setValue(null);
+                    }
+                });
+    }
+
     @PostMapping(consumes = "multipart/form-data", value = "/add-watermark")
     @Operation(
             summary = "Add watermark to a PDF file",
@@ -69,7 +84,7 @@ public class WatermarkController {
         int widthSpacer = request.getWidthSpacer();
         int heightSpacer = request.getHeightSpacer();
         String customColor = request.getCustomColor();
-        boolean convertPdfToImage = request.isConvertPDFToImage();
+        boolean convertPdfToImage = Boolean.TRUE.equals(request.getConvertPDFToImage());
 
         // Load the input PDF
         PDDocument document = pdfDocumentFactory.load(pdfFile);

src/main/java/stirling/software/SPDF/model/api/Email.java

@@ -4,7 +4,6 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 
 import io.swagger.v3.oas.annotations.media.Schema;
 
-
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 import lombok.NoArgsConstructor;

src/main/java/stirling/software/SPDF/model/api/GeneralFile.java

@@ -11,6 +11,9 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode
 public class GeneralFile {
 
-    @Schema(description = "The input file")
+    @Schema(
+            description = "The input file",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            format = "binary")
     private MultipartFile fileInput;
 }

src/main/java/stirling/software/SPDF/model/api/HandleDataRequest.java

@@ -11,9 +11,12 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode
 public class HandleDataRequest {
 
-    @Schema(description = "The input files")
+    @Schema(description = "The input files", requiredMode = Schema.RequiredMode.REQUIRED)
     private MultipartFile[] fileInput;
 
-    @Schema(description = "JSON String")
+    @Schema(
+            description = "JSON String",
+            defaultValue = "{}",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String json;
 }

src/main/java/stirling/software/SPDF/model/api/ImageFile.java

@@ -10,6 +10,9 @@ import lombok.EqualsAndHashCode;
 @Data
 @EqualsAndHashCode
 public class ImageFile {
-    @Schema(description = "The input image file")
+    @Schema(
+            description = "The input image file",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            format = "binary")
     private MultipartFile fileInput;
 }

src/main/java/stirling/software/SPDF/model/api/MultiplePDFFiles.java

@@ -10,6 +10,6 @@ import lombok.EqualsAndHashCode;
 @Data
 @EqualsAndHashCode
 public class MultiplePDFFiles {
-    @Schema(description = "The input PDF files", type = "array", format = "binary")
+    @Schema(description = "The input PDF files", requiredMode = Schema.RequiredMode.REQUIRED)
     private MultipartFile[] fileInput;
 }

src/main/java/stirling/software/SPDF/model/api/PDFComparison.java

@@ -11,6 +11,7 @@ public class PDFComparison extends PDFFile {
 
     @Schema(
             description = "The comparison type, accepts Greater, Equal, Less than",
-            allowableValues = {"Greater", "Equal", "Less"})
+            allowableValues = {"Greater", "Equal", "Less"},
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String comparator;
 }

src/main/java/stirling/software/SPDF/model/api/PDFComparisonAndCount.java

@@ -8,6 +8,6 @@ import lombok.EqualsAndHashCode;
 @Data
 @EqualsAndHashCode(callSuper = true)
 public class PDFComparisonAndCount extends PDFComparison {
-    @Schema(description = "Count")
-    private String pageCount;
+    @Schema(description = "Count", requiredMode = Schema.RequiredMode.REQUIRED, defaultValue = "0")
+    private int pageCount;
 }

src/main/java/stirling/software/SPDF/model/api/PDFExtractImagesRequest.java

@@ -11,6 +11,8 @@ public class PDFExtractImagesRequest extends PDFWithImageFormatRequest {
 
     @Schema(
             description =
-                    "Boolean to enable/disable the saving of duplicate images, true to enable duplicates")
-    private boolean allowDuplicates;
+                    "Boolean to enable/disable the saving of duplicate images, true to enable"
+                            + " duplicates",
+            defaultValue = "false")
+    private Boolean allowDuplicates;
 }

src/main/java/stirling/software/SPDF/model/api/PDFFile.java

@@ -12,6 +12,10 @@ import lombok.NoArgsConstructor;
 @NoArgsConstructor
 @EqualsAndHashCode
 public class PDFFile {
-    @Schema(description = "The input PDF file", format = "binary")
+    @Schema(
+            description = "The input PDF file",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            contentMediaType = "application/pdf",
+            format = "binary")
     private MultipartFile fileInput;
 }

src/main/java/stirling/software/SPDF/model/api/PDFWithImageFormatRequest.java

@@ -11,6 +11,8 @@ public class PDFWithImageFormatRequest extends PDFFile {
 
     @Schema(
             description = "The output image format e.g., 'png', 'jpeg', or 'gif'",
-            allowableValues = {"png", "jpeg", "gif"})
+            allowableValues = {"png", "jpeg", "gif"},
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "png")
     private String format;
 }

src/main/java/stirling/software/SPDF/model/api/PDFWithPageNums.java

@@ -21,9 +21,9 @@ public class PDFWithPageNums extends PDFFile {
             description =
                     "The pages to select, Supports ranges (e.g., '1,3,5-9'), or 'all' or functions in the"
                             + " format 'an+b' where 'a' is the multiplier of the page number 'n', and 'b' is a"
-                            + " constant (e.g., '2n+1', '3n', '6n-5')\"",
+                            + " constant (e.g., '2n+1', '3n', '6n-5')",
             defaultValue = "all",
-            requiredMode = RequiredMode.NOT_REQUIRED)
+            requiredMode = RequiredMode.REQUIRED)
     private String pageNumbers;
 
     @Hidden

src/main/java/stirling/software/SPDF/model/api/PDFWithPageSize.java

@@ -11,7 +11,9 @@ public class PDFWithPageSize extends PDFFile {
 
     @Schema(
             description =
-                    "The scale of pages in the output PDF. Acceptable values are A0-A6, LETTER, LEGAL, KEEP.",
+                    "The scale of pages in the output PDF. Acceptable values are A0-A6, LETTER,"
+                            + " LEGAL, KEEP.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"A0", "A1", "A2", "A3", "A4", "A5", "A6", "LETTER", "LEGAL", "KEEP"})
     private String pageSize;
 }

src/main/java/stirling/software/SPDF/model/api/SplitPdfByChaptersRequest.java

@@ -8,12 +8,22 @@ import lombok.EqualsAndHashCode;
 @Data
 @EqualsAndHashCode(callSuper = false)
 public class SplitPdfByChaptersRequest extends PDFFile {
-    @Schema(description = "Whether to include Metadata or not", example = "true")
+    @Schema(
+            description = "Whether to include Metadata or not",
+            defaultValue = "true",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private Boolean includeMetadata;
 
-    @Schema(description = "Whether to allow duplicates or not", example = "true")
+    @Schema(
+            description = "Whether to allow duplicates or not",
+            defaultValue = "true",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private Boolean allowDuplicates;
 
-    @Schema(description = "Maximum bookmark level required", example = "2")
+    @Schema(
+            description = "Maximum bookmark level required",
+            minimum = "0",
+            defaultValue = "2",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private Integer bookmarkLevel;
 }

src/main/java/stirling/software/SPDF/model/api/SplitPdfBySectionsRequest.java

@@ -8,12 +8,23 @@ import lombok.EqualsAndHashCode;
 @Data
 @EqualsAndHashCode(callSuper = true)
 public class SplitPdfBySectionsRequest extends PDFFile {
-    @Schema(description = "Number of horizontal divisions for each PDF page", example = "2")
+    @Schema(
+            description = "Number of horizontal divisions for each PDF page",
+            defaultValue = "0",
+            minimum = "0",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private int horizontalDivisions;
 
-    @Schema(description = "Number of vertical divisions for each PDF page", example = "2")
+    @Schema(
+            description = "Number of vertical divisions for each PDF page",
+            defaultValue = "1",
+            minimum = "0",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private int verticalDivisions;
 
-    @Schema(description = "Merge the split documents into a single PDF", example = "true")
-    private boolean merge;
+    @Schema(
+            description = "Merge the split documents into a single PDF",
+            defaultValue = "true",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean merge;
 }

src/main/java/stirling/software/SPDF/model/api/converters/ConvertPDFToMarkdown.java

@@ -23,9 +23,9 @@ public class ConvertPDFToMarkdown {
             summary = "Convert PDF to Markdown",
             description =
                     "This endpoint converts a PDF file to Markdown format. Input:PDF Output:Markdown Type:SISO")
-    public ResponseEntity<byte[]> processPdfToMarkdown(@ModelAttribute PDFFile request)
+    public ResponseEntity<byte[]> processPdfToMarkdown(@ModelAttribute PDFFile file)
             throws Exception {
-        MultipartFile inputFile = request.getFileInput();
+        MultipartFile inputFile = file.getFileInput();
         PDFToFile pdfToFile = new PDFToFile();
         return pdfToFile.processPdfToMarkdown(inputFile);
     }

src/main/java/stirling/software/SPDF/model/api/converters/ConvertToImageRequest.java

@@ -5,33 +5,38 @@ import io.swagger.v3.oas.annotations.media.Schema;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 
-import stirling.software.SPDF.model.api.PDFFile;
+import stirling.software.SPDF.model.api.PDFWithPageNums;
 
 @Data
 @EqualsAndHashCode(callSuper = true)
-public class ConvertToImageRequest extends PDFFile {
+public class ConvertToImageRequest extends PDFWithPageNums {
 
     @Schema(
             description = "The output image format",
-            allowableValues = {"png", "jpeg", "jpg", "gif", "webp"})
+            defaultValue = "png",
+            allowableValues = {"png", "jpeg", "jpg", "gif", "webp"},
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String imageFormat;
 
     @Schema(
             description =
-                    "Choose between a single image containing all pages or separate images for each page",
-            allowableValues = {"single", "multiple"})
+                    "Choose between a single image containing all pages or separate images for each"
+                            + " page",
+            defaultValue = "multiple",
+            allowableValues = {"single", "multiple"},
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String singleOrMultiple;
 
-    @Schema(
-            description =
-                    "The pages to select, Supports ranges (e.g., '1,3,5-9'), or 'all' or functions in the format 'an+b' where 'a' is the multiplier of the page number 'n', and 'b' is a constant (e.g., '2n+1', '3n', '6n-5')\"")
-    private String pageNumbers;
-
     @Schema(
             description = "The color type of the output image(s)",
-            allowableValues = {"color", "greyscale", "blackwhite"})
+            defaultValue = "color",
+            allowableValues = {"color", "greyscale", "blackwhite"},
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String colorType;
 
-    @Schema(description = "The DPI (dots per inch) for the output image(s)")
-    private String dpi;
+    @Schema(
+            description = "The DPI (dots per inch) for the output image(s)",
+            defaultValue = "300",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Integer dpi;
 }

src/main/java/stirling/software/SPDF/model/api/converters/ConvertToPdfRequest.java

@@ -11,21 +11,28 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode
 public class ConvertToPdfRequest {
 
-    @Schema(description = "The input images to be converted to a PDF file")
+    @Schema(
+            description = "The input images to be converted to a PDF file",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private MultipartFile[] fileInput;
 
     @Schema(
             description = "Option to determine how the image will fit onto the page",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "fillPage",
             allowableValues = {"fillPage", "fitDocumentToImage", "maintainAspectRatio"})
     private String fitOption;
 
     @Schema(
             description = "The color type of the output image(s)",
+            defaultValue = "color",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"color", "greyscale", "blackwhite"})
     private String colorType;
 
     @Schema(
             description = "Whether to automatically rotate the images to better fit the PDF page",
-            example = "true")
-    private boolean autoRotate;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "false")
+    private Boolean autoRotate;
 }

src/main/java/stirling/software/SPDF/model/api/converters/HTMLToPdfRequest.java

@@ -13,6 +13,7 @@ public class HTMLToPdfRequest extends PDFFile {
 
     @Schema(
             description = "Zoom level for displaying the website. Default is '1'.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             defaultValue = "1")
     private float zoom;
 }

src/main/java/stirling/software/SPDF/model/api/converters/PdfToBookRequest.java

@@ -13,6 +13,7 @@ public class PdfToBookRequest extends PDFFile {
 
     @Schema(
             description = "The output Ebook format",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {
                 "epub", "mobi", "azw3", "docx", "rtf", "txt", "html", "lit", "fb2", "pdb", "lrf"
             })

src/main/java/stirling/software/SPDF/model/api/converters/PdfToPdfARequest.java

@@ -13,6 +13,7 @@ public class PdfToPdfARequest extends PDFFile {
 
     @Schema(
             description = "The output PDF/A type",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"pdfa", "pdfa-1"})
     private String outputFormat;
 }

src/main/java/stirling/software/SPDF/model/api/converters/PdfToPresentationRequest.java

@@ -13,6 +13,7 @@ public class PdfToPresentationRequest extends PDFFile {
 
     @Schema(
             description = "The output Presentation format",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"ppt", "pptx", "odp"})
     private String outputFormat;
 }

src/main/java/stirling/software/SPDF/model/api/converters/PdfToTextOrRTFRequest.java

@@ -13,6 +13,7 @@ public class PdfToTextOrRTFRequest extends PDFFile {
 
     @Schema(
             description = "The output Text or RTF format",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"rtf", "txt"})
     private String outputFormat;
 }

src/main/java/stirling/software/SPDF/model/api/converters/PdfToWordRequest.java

@@ -13,6 +13,7 @@ public class PdfToWordRequest extends PDFFile {
 
     @Schema(
             description = "The output Word document format",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"doc", "docx", "odt"})
     private String outputFormat;
 }

src/main/java/stirling/software/SPDF/model/api/filter/ContainsTextRequest.java

@@ -11,6 +11,9 @@ import stirling.software.SPDF.model.api.PDFWithPageNums;
 @EqualsAndHashCode(callSuper = true)
 public class ContainsTextRequest extends PDFWithPageNums {
 
-    @Schema(description = "The text to check for", requiredMode = Schema.RequiredMode.REQUIRED)
+    @Schema(
+            description = "The text to check for",
+            defaultValue = "text",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String text;
 }

src/main/java/stirling/software/SPDF/model/api/filter/FileSizeRequest.java

@@ -11,6 +11,9 @@ import stirling.software.SPDF.model.api.PDFComparison;
 @EqualsAndHashCode(callSuper = true)
 public class FileSizeRequest extends PDFComparison {
 
-    @Schema(description = "File Size", requiredMode = Schema.RequiredMode.REQUIRED)
-    private String fileSize;
+    @Schema(
+            description = "Size of the file in bytes",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "0")
+    private long fileSize;
 }

src/main/java/stirling/software/SPDF/model/api/filter/PageRotationRequest.java

@@ -11,6 +11,9 @@ import stirling.software.SPDF.model.api.PDFComparison;
 @EqualsAndHashCode(callSuper = true)
 public class PageRotationRequest extends PDFComparison {
 
-    @Schema(description = "Rotation in degrees", requiredMode = Schema.RequiredMode.REQUIRED)
+    @Schema(
+            description = "Rotation in degrees",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "0")
     private int rotation;
 }

src/main/java/stirling/software/SPDF/model/api/filter/PageSizeRequest.java

@@ -11,6 +11,10 @@ import stirling.software.SPDF.model.api.PDFComparison;
 @EqualsAndHashCode(callSuper = true)
 public class PageSizeRequest extends PDFComparison {
 
-    @Schema(description = "Standard Page Size", requiredMode = Schema.RequiredMode.REQUIRED)
+    @Schema(
+            description = "Standard Page Size",
+            allowableValues = {"A0", "A1", "A2", "A3", "A4", "A5", "A6", "LETTER", "LEGAL"},
+            defaultValue = "A4",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String standardPageSize;
 }

src/main/java/stirling/software/SPDF/model/api/general/MergeMultiplePagesRequest.java

@@ -13,10 +13,12 @@ public class MergeMultiplePagesRequest extends PDFFile {
 
     @Schema(
             description = "The number of pages to fit onto a single sheet in the output PDF.",
-            type = "integer",
+            type = "number",
+            defaultValue = "2",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"2", "3", "4", "9", "16"})
     private int pagesPerSheet;
 
     @Schema(description = "Boolean for if you wish to add border around the pages")
-    private boolean addBorder;
+    private Boolean addBorder;
 }

src/main/java/stirling/software/SPDF/model/api/general/MergePdfsRequest.java

@@ -20,12 +20,16 @@ public class MergePdfsRequest extends MultiplePDFFiles {
                 "byDateCreated",
                 "byPDFTitle"
             },
+            requiredMode = Schema.RequiredMode.REQUIRED,
             defaultValue = "orderProvided")
     private String sortType = "orderProvided";
 
     @Schema(
             description =
-                    "Flag indicating whether to remove certification signatures from the merged PDF. If true, all certification signatures will be removed from the final merged document.",
-            example = "true")
-    private boolean isRemoveCertSign;
+                    "Flag indicating whether to remove certification signatures from the merged"
+                            + " PDF. If true, all certification signatures will be removed from the"
+                            + " final merged document.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "true")
+    private Boolean removeCertSign;
 }

src/main/java/stirling/software/SPDF/model/api/general/OverlayPdfsRequest.java

@@ -15,21 +15,32 @@ public class OverlayPdfsRequest extends PDFFile {
 
     @Schema(
             description =
-                    "An array of PDF files to be used as overlays on the base PDF. The order in these files is applied based on the selected mode.")
+                    "An array of PDF files to be used as overlays on the base PDF. The order in"
+                            + " these files is applied based on the selected mode.",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private MultipartFile[] overlayFiles;
 
     @Schema(
             description =
-                    "The mode of overlaying: 'SequentialOverlay' for sequential application, 'InterleavedOverlay' for round-robin application, 'FixedRepeatOverlay' for fixed repetition based on provided counts",
+                    "The mode of overlaying: 'SequentialOverlay' for sequential application,"
+                            + " 'InterleavedOverlay' for round-robin application, 'FixedRepeatOverlay'"
+                            + " for fixed repetition based on provided counts",
+            allowableValues = {"SequentialOverlay", "InterleavedOverlay", "FixedRepeatOverlay"},
             requiredMode = Schema.RequiredMode.REQUIRED)
     private String overlayMode;
 
     @Schema(
             description =
-                    "An array of integers specifying the number of times each corresponding overlay file should be applied in the 'FixedRepeatOverlay' mode. This should match the length of the overlayFiles array.",
+                    "An array of integers specifying the number of times each corresponding overlay"
+                            + " file should be applied in the 'FixedRepeatOverlay' mode. This should"
+                            + " match the length of the overlayFiles array.",
             requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private int[] counts;
 
-    @Schema(description = "Overlay position 0 is Foregound, 1 is Background")
+    @Schema(
+            description = "Overlay position 0 is Foregound, 1 is Background",
+            allowableValues = {"0", "1"},
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            type = "number")
     private int overlayPosition;
 }

src/main/java/stirling/software/SPDF/model/api/general/RotatePDFRequest.java

@@ -14,6 +14,8 @@ public class RotatePDFRequest extends PDFFile {
     @Schema(
             description =
                     "The angle by which to rotate the PDF file. This should be a multiple of 90.",
-            example = "90")
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            allowableValues = {"0", "90", "180", "270"},
+            defaultValue = "90")
     private Integer angle;
 }

src/main/java/stirling/software/SPDF/model/api/general/ScalePagesRequest.java

@@ -12,7 +12,11 @@ import stirling.software.SPDF.model.api.PDFWithPageSize;
 public class ScalePagesRequest extends PDFWithPageSize {
 
     @Schema(
+            minimum = "0",
+            defaultValue = "1",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             description =
-                    "The scale of the content on the pages of the output PDF. Acceptable values are floats.")
+                    "The scale of the content on the pages of the output PDF. Acceptable values are"
+                            + " floats.")
     private float scaleFactor;
 }

src/main/java/stirling/software/SPDF/model/api/misc/AddPageNumbersRequest.java

@@ -22,6 +22,7 @@ public class AddPageNumbersRequest extends PDFWithPageNums {
     @Schema(
             description = "Font size for page numbers",
             minimum = "1",
+            defaultValue = "12",
             requiredMode = RequiredMode.REQUIRED)
     private float fontSize;
 
@@ -33,15 +34,18 @@ public class AddPageNumbersRequest extends PDFWithPageNums {
 
     @Schema(
             description =
-                    "Position: 1-9 representing positions on the page (1=top-left, 5=center, 9=bottom-right)",
-            minimum = "1",
-            maximum = "9",
+                    "Position: 1-9 representing positions on the page (1=top-left, 2=top-center,"
+                            + " 3=top-right, 4=middle-left, 5=middle-center, 6=middle-right,"
+                            + " 7=bottom-left, 8=bottom-center, 9=bottom-right)",
+            allowableValues = {"1", "2", "3", "4", "5", "6", "7", "8", "9"},
+            defaultValue = "8",
             requiredMode = RequiredMode.REQUIRED)
     private int position;
 
     @Schema(
             description = "Starting number for page numbering",
             minimum = "1",
+            defaultValue = "1",
             requiredMode = RequiredMode.REQUIRED)
     private int startingNumber;
 
@@ -53,7 +57,8 @@ public class AddPageNumbersRequest extends PDFWithPageNums {
 
     @Schema(
             description =
-                    "Custom text pattern. Available variables: {n}=current page number, {total}=total pages, {filename}=original filename",
+                    "Custom text pattern. Available variables: {n}=current page number,"
+                            + " {total}=total pages, {filename}=original filename",
             example = "Page {n} of {total}",
             defaultValue = "{n}",
             requiredMode = RequiredMode.NOT_REQUIRED)

src/main/java/stirling/software/SPDF/model/api/misc/AddStampRequest.java

@@ -19,51 +19,69 @@ public class AddStampRequest extends PDFWithPageNums {
             requiredMode = Schema.RequiredMode.REQUIRED)
     private String stampType;
 
-    @Schema(description = "The stamp text")
+    @Schema(description = "The stamp text", defaultValue = "Stirling Software")
     private String stampText;
 
     @Schema(description = "The stamp image")
     private MultipartFile stampImage;
 
     @Schema(
-            description = "The selected alphabet",
+            description = "The selected alphabet of the stamp text",
             allowableValues = {"roman", "arabic", "japanese", "korean", "chinese"},
             defaultValue = "roman")
     private String alphabet = "roman";
 
-    @Schema(description = "The font size of the stamp text", example = "30")
-    private float fontSize = 30;
+    @Schema(
+            description = "The font size of the stamp text and image",
+            defaultValue = "30",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private float fontSize;
 
-    @Schema(description = "The rotation of the stamp in degrees", example = "0")
-    private float rotation = 0;
+    @Schema(
+            description = "The rotation of the stamp in degrees",
+            defaultValue = "0",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private float rotation;
 
-    @Schema(description = "The opacity of the stamp (0.0 - 1.0)", example = "0.5")
+    @Schema(
+            description = "The opacity of the stamp (0.0 - 1.0)",
+            defaultValue = "0.5",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private float opacity;
 
     @Schema(
             description =
-                    "Position for stamp placement based on a 1-9 grid (1: bottom-left, 2: bottom-center, ..., 9: top-right)",
-            example = "1")
+                    "Position for stamp placement based on a 1-9 grid (1: bottom-left, 2: bottom-center,"
+                            + " 3: bottom-right, 4: middle-left, 5: middle-center, 6: middle-right,"
+                            + " 7: top-left, 8: top-center, 9: top-right)",
+            allowableValues = {"1", "2", "3", "4", "5", "6", "7", "8", "9"},
+            defaultValue = "5",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private int position;
 
     @Schema(
             description =
-                    "Override X coordinate for stamp placement. If set, it will override the position-based calculation. Negative value means no override.",
-            example = "-1")
-    private float overrideX = -1; // Default to -1 indicating no override
+                    "Override X coordinate for stamp placement. If set, it will override the"
+                            + " position-based calculation. Negative value means no override.",
+            defaultValue = "-1",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private float overrideX; // Default to -1 indicating no override
 
     @Schema(
             description =
-                    "Override Y coordinate for stamp placement. If set, it will override the position-based calculation. Negative value means no override.",
-            example = "-1")
-    private float overrideY = -1; // Default to -1 indicating no override
+                    "Override Y coordinate for stamp placement. If set, it will override the"
+                            + " position-based calculation. Negative value means no override.",
+            defaultValue = "-1",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private float overrideY; // Default to -1 indicating no override
 
     @Schema(
             description = "Specifies the margin size for the stamp.",
             allowableValues = {"small", "medium", "large", "x-large"},
-            defaultValue = "medium")
-    private String customMargin = "medium";
+            defaultValue = "medium",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private String customMargin;
 
-    @Schema(description = "The color for stamp", defaultValue = "#d3d3d3")
-    private String customColor = "#d3d3d3";
+    @Schema(description = "The color of the stamp text", defaultValue = "#d3d3d3")
+    private String customColor;
 }

src/main/java/stirling/software/SPDF/model/api/misc/AutoSplitPdfRequest.java

@@ -16,5 +16,5 @@ public class AutoSplitPdfRequest extends PDFFile {
                     "Flag indicating if the duplex mode is active, where the page after the divider also gets removed.",
             requiredMode = Schema.RequiredMode.NOT_REQUIRED,
             defaultValue = "false")
-    private boolean duplexMode;
+    private Boolean duplexMode;
 }

src/main/java/stirling/software/SPDF/model/api/misc/ExtractHeaderRequest.java

@@ -16,5 +16,5 @@ public class ExtractHeaderRequest extends PDFFile {
                     "Flag indicating whether to use the first text as a fallback if no suitable title is found. Defaults to false.",
             requiredMode = Schema.RequiredMode.NOT_REQUIRED,
             defaultValue = "false")
-    private boolean useFirstTextAsFallback;
+    private Boolean useFirstTextAsFallback;
 }

src/main/java/stirling/software/SPDF/model/api/misc/ExtractImageScansRequest.java

@@ -12,36 +12,37 @@ import lombok.EqualsAndHashCode;
 public class ExtractImageScansRequest {
     @Schema(
             description = "The input file containing image scans",
-            requiredMode = Schema.RequiredMode.REQUIRED)
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            format = "binary")
     private MultipartFile fileInput;
 
     @Schema(
             description = "The angle threshold for the image scan extraction",
-            defaultValue = "5",
-            example = "5")
-    private int angleThreshold = 5;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "5")
+    private int angleThreshold;
 
     @Schema(
             description = "The tolerance for the image scan extraction",
-            defaultValue = "20",
-            example = "20")
-    private int tolerance = 20;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "20")
+    private int tolerance;
 
     @Schema(
             description = "The minimum area for the image scan extraction",
-            defaultValue = "8000",
-            example = "8000")
-    private int minArea = 8000;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "8000")
+    private int minArea;
 
     @Schema(
             description = "The minimum contour area for the image scan extraction",
-            defaultValue = "500",
-            example = "500")
-    private int minContourArea = 500;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "500")
+    private int minContourArea;
 
     @Schema(
             description = "The border size for the image scan extraction",
-            defaultValue = "1",
-            example = "1")
-    private int borderSize = 1;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "1")
+    private int borderSize;
 }

src/main/java/stirling/software/SPDF/model/api/misc/FlattenRequest.java

@@ -13,6 +13,9 @@ public class FlattenRequest extends PDFFile {
 
     @Schema(
             description =
-                    "True to flatten only the forms, false to flatten full PDF (Convert page to image)")
+                    "True to flatten only the forms, false to flatten full PDF (Convert page to"
+                            + " image)",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "false")
     private Boolean flattenOnlyForms;
 }

src/main/java/stirling/software/SPDF/model/api/misc/MetadataRequest.java

@@ -13,38 +13,72 @@ import stirling.software.SPDF.model.api.PDFFile;
 @EqualsAndHashCode(callSuper = true)
 public class MetadataRequest extends PDFFile {
 
-    @Schema(description = "Delete all metadata if set to true")
-    private boolean deleteAll;
+    @Schema(
+            description = "Delete all metadata if set to true",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean deleteAll;
 
-    @Schema(description = "The author of the document")
+    @Schema(
+            description = "The author of the document",
+            defaultValue = "author",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String author;
 
-    @Schema(description = "The creation date of the document (format: yyyy/MM/dd HH:mm:ss)")
+    @Schema(
+            description = "The creation date of the document (format: yyyy/MM/dd HH:mm:ss)",
+            pattern = "yyyy/MM/dd HH:mm:ss",
+            defaultValue = "2023/10/01 12:00:00",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String creationDate;
 
-    @Schema(description = "The creator of the document")
+    @Schema(
+            description = "The creator of the document",
+            defaultValue = "creator",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String creator;
 
-    @Schema(description = "The keywords for the document")
+    @Schema(
+            description = "The keywords for the document",
+            defaultValue = "keywords",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String keywords;
 
-    @Schema(description = "The modification date of the document (format: yyyy/MM/dd HH:mm:ss)")
+    @Schema(
+            description = "The modification date of the document (format: yyyy/MM/dd HH:mm:ss)",
+            pattern = "yyyy/MM/dd HH:mm:ss",
+            defaultValue = "2023/10/01 12:00:00",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String modificationDate;
 
-    @Schema(description = "The producer of the document")
+    @Schema(
+            description = "The producer of the document",
+            defaultValue = "producer",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String producer;
 
-    @Schema(description = "The subject of the document")
+    @Schema(
+            description = "The subject of the document",
+            defaultValue = "subject",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String subject;
 
-    @Schema(description = "The title of the document")
+    @Schema(
+            description = "The title of the document",
+            defaultValue = "title",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String title;
 
-    @Schema(description = "The trapped status of the document")
+    @Schema(
+            description = "The trapped status of the document",
+            defaultValue = "False",
+            allowableValues = {"True", "False", "Unknown"},
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String trapped;
 
     @Schema(
             description =
-                    "Map list of key and value of custom parameters. Note these must start with customKey and customValue if they are non-standard")
+                    "Map list of key and value of custom parameters. Note these must start with"
+                            + " customKey and customValue if they are non-standard")
     private Map<String, String> allRequestParams;
 }

src/main/java/stirling/software/SPDF/model/api/misc/OptimizePdfRequest.java

@@ -13,30 +13,36 @@ public class OptimizePdfRequest extends PDFFile {
 
     @Schema(
             description =
-                    "The level of optimization to apply to the PDF file. Higher values indicate greater compression but may reduce quality.",
+                    "The level of optimization to apply to the PDF file. Higher values indicate"
+                            + " greater compression but may reduce quality.",
+            defaultValue = "5",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"1", "2", "3", "4", "5", "6", "7", "8", "9"})
     private Integer optimizeLevel;
 
-    @Schema(description = "The expected output size, e.g. '100MB', '25KB', etc.")
+    @Schema(
+            description = "The expected output size, e.g. '100MB', '25KB', etc.",
+            defaultValue = "25KB",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String expectedOutputSize;
 
     @Schema(
             description = "Whether to linearize the PDF for faster web viewing. Default is false.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             defaultValue = "false")
     private Boolean linearize = false;
 
     @Schema(
             description =
-                    "Whether to normalize the PDF content for better compatibility. Default is false.",
+                    "Whether to normalize the PDF content for better compatibility. Default is"
+                            + " false.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             defaultValue = "false")
     private Boolean normalize = false;
 
     @Schema(
             description = "Whether to convert the PDF to grayscale. Default is false.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             defaultValue = "false")
     private Boolean grayscale = false;
-
-    public Boolean getGrayscale() {
-        return grayscale;
-    }
 }

src/main/java/stirling/software/SPDF/model/api/misc/OverlayImageRequest.java

@@ -13,21 +13,27 @@ import stirling.software.SPDF.model.api.PDFFile;
 @EqualsAndHashCode(callSuper = true)
 public class OverlayImageRequest extends PDFFile {
 
-    @Schema(description = "The image file to be overlaid onto the PDF.")
+    @Schema(
+            description = "The image file to be overlaid onto the PDF.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            format = "binary")
     private MultipartFile imageFile;
 
     @Schema(
             description = "The x-coordinate at which to place the top-left corner of the image.",
-            example = "0")
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "0")
     private float x;
 
     @Schema(
             description = "The y-coordinate at which to place the top-left corner of the image.",
-            example = "0")
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "0")
     private float y;
 
     @Schema(
             description = "Whether to overlay the image onto every page of the PDF.",
-            example = "false")
-    private boolean everyPage;
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "false")
+    private Boolean everyPage;
 }

src/main/java/stirling/software/SPDF/model/api/misc/ProcessPdfWithOcrRequest.java

@@ -13,16 +13,21 @@ import stirling.software.SPDF.model.api.PDFFile;
 @EqualsAndHashCode(callSuper = true)
 public class ProcessPdfWithOcrRequest extends PDFFile {
 
-    @Schema(description = "List of languages to use in OCR processing")
+    @Schema(
+            description = "List of languages to use in OCR processing, e.g., 'eng', 'deu'",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "[\"eng\"]")
     private List<String> languages;
 
     @Schema(
             description = "Specify the OCR type, e.g., 'skip-text', 'force-ocr', or 'Normal'",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"skip-text", "force-ocr", "Normal"})
     private String ocrType;
 
     @Schema(
             description = "Specify the OCR render type, either 'hocr' or 'sandwich'",
+            requiredMode = Schema.RequiredMode.REQUIRED,
             allowableValues = {"hocr", "sandwich"},
             defaultValue = "hocr")
     private String ocrRenderType = "hocr";

src/main/java/stirling/software/SPDF/model/api/misc/RemoveBlankPagesRequest.java

@@ -13,13 +13,17 @@ public class RemoveBlankPagesRequest extends PDFFile {
 
     @Schema(
             description = "The threshold value to determine blank pages",
-            example = "10",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            minimum = "0",
+            maximum = "255",
             defaultValue = "10")
-    private int threshold = 10;
+    private int threshold;
 
     @Schema(
             description = "The percentage of white color on a page to consider it as blank",
-            example = "99.9",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            minimum = "0.1",
+            maximum = "100",
             defaultValue = "99.9")
-    private float whitePercent = 99.9f;
+    private float whitePercent;
 }

src/main/java/stirling/software/SPDF/model/api/misc/ReplaceAndInvertColorRequest.java

@@ -13,12 +13,16 @@ public class ReplaceAndInvertColorRequest extends PDFFile {
 
     @Schema(
             description = "Replace and Invert color options of a pdf.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "HIGH_CONTRAST_COLOR",
             allowableValues = {"HIGH_CONTRAST_COLOR", "CUSTOM_COLOR", "FULL_INVERSION"})
     private ReplaceAndInvert replaceAndInvertOption;
 
     @Schema(
             description =
                     "If HIGH_CONTRAST_COLOR option selected, then pick the default color option for text and background.",
+            requiredMode = Schema.RequiredMode.REQUIRED,
+            defaultValue = "WHITE_TEXT_ON_BLACK",
             allowableValues = {
                 "WHITE_TEXT_ON_BLACK",
                 "BLACK_TEXT_ON_WHITE",

src/main/java/stirling/software/SPDF/model/api/security/AddPasswordRequest.java

@@ -13,45 +13,50 @@ public class AddPasswordRequest extends PDFFile {
 
     @Schema(
             description =
-                    "The owner password to be added to the PDF file (Restricts what can be done with the document once it is opened)",
-            defaultValue = "")
+                    "The owner password to be added to the PDF file (Restricts what can be done"
+                            + " with the document once it is opened)",
+            format = "password")
     private String ownerPassword;
 
     @Schema(
             description =
-                    "The password to be added to the PDF file (Restricts the opening of the document itself.)",
-            defaultValue = "")
+                    "The password to be added to the PDF file (Restricts the opening of the"
+                            + " document itself.)",
+            format = "password")
     private String password;
 
     @Schema(
             description = "The length of the encryption key",
             allowableValues = {"40", "128", "256"},
-            defaultValue = "256")
+            defaultValue = "256",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private int keyLength = 256;
 
-    @Schema(description = "Whether document assembly is prevented", example = "false")
-    private boolean preventAssembly;
+    @Schema(description = "Whether document assembly is prevented", defaultValue = "false")
+    private Boolean preventAssembly;
 
-    @Schema(description = "Whether content extraction is prevented", example = "false")
-    private boolean preventExtractContent;
+    @Schema(description = "Whether content extraction is prevented", defaultValue = "false")
+    private Boolean preventExtractContent;
 
     @Schema(
             description = "Whether content extraction for accessibility is prevented",
-            example = "false")
-    private boolean preventExtractForAccessibility;
+            defaultValue = "false")
+    private Boolean preventExtractForAccessibility;
 
-    @Schema(description = "Whether form filling is prevented", example = "false")
-    private boolean preventFillInForm;
+    @Schema(description = "Whether form filling is prevented", defaultValue = "false")
+    private Boolean preventFillInForm;
 
-    @Schema(description = "Whether document modification is prevented", example = "false")
-    private boolean preventModify;
+    @Schema(description = "Whether document modification is prevented", defaultValue = "false")
+    private Boolean preventModify;
 
-    @Schema(description = "Whether modification of annotations is prevented", example = "false")
-    private boolean preventModifyAnnotations;
+    @Schema(
+            description = "Whether modification of annotations is prevented",
+            defaultValue = "false")
+    private Boolean preventModifyAnnotations;
 
-    @Schema(description = "Whether printing of the document is prevented", example = "false")
-    private boolean preventPrinting;
+    @Schema(description = "Whether printing of the document is prevented", defaultValue = "false")
+    private Boolean preventPrinting;
 
-    @Schema(description = "Whether faithful printing is prevented", example = "false")
-    private boolean preventPrintingFaithful;
+    @Schema(description = "Whether faithful printing is prevented", defaultValue = "false")
+    private Boolean preventPrintingFaithful;
 }

src/main/java/stirling/software/SPDF/model/api/security/AddWatermarkRequest.java

@@ -19,7 +19,7 @@ public class AddWatermarkRequest extends PDFFile {
             requiredMode = Schema.RequiredMode.REQUIRED)
     private String watermarkType;
 
-    @Schema(description = "The watermark text")
+    @Schema(description = "The watermark text", defaultValue = "Stirling Software")
     private String watermarkText;
 
     @Schema(description = "The watermark image")
@@ -29,26 +29,29 @@ public class AddWatermarkRequest extends PDFFile {
             description = "The selected alphabet",
             allowableValues = {"roman", "arabic", "japanese", "korean", "chinese"},
             defaultValue = "roman")
-    private String alphabet = "roman";
+    private String alphabet;
 
-    @Schema(description = "The font size of the watermark text", example = "30")
-    private float fontSize = 30;
+    @Schema(description = "The font size of the watermark text", defaultValue = "30")
+    private float fontSize;
 
-    @Schema(description = "The rotation of the watermark in degrees", example = "0")
-    private float rotation = 0;
+    @Schema(description = "The rotation of the watermark in degrees", defaultValue = "0")
+    private float rotation;
 
-    @Schema(description = "The opacity of the watermark (0.0 - 1.0)", example = "0.5")
+    @Schema(description = "The opacity of the watermark (0.0 - 1.0)", defaultValue = "0.5")
     private float opacity;
 
-    @Schema(description = "The width spacer between watermark elements", example = "50")
+    @Schema(description = "The width spacer between watermark elements", defaultValue = "50")
     private int widthSpacer;
 
-    @Schema(description = "The height spacer between watermark elements", example = "50")
+    @Schema(description = "The height spacer between watermark elements", defaultValue = "50")
     private int heightSpacer;
 
     @Schema(description = "The color for watermark", defaultValue = "#d3d3d3")
-    private String customColor = "#d3d3d3";
+    private String customColor;
 
-    @Schema(description = "Convert the redacted PDF to an image", defaultValue = "false")
-    private boolean convertPDFToImage;
+    @Schema(
+            description = "Convert the redacted PDF to an image",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean convertPDFToImage;
 }

src/main/java/stirling/software/SPDF/model/api/security/ManualRedactPdfRequest.java

@@ -12,12 +12,20 @@ import stirling.software.SPDF.model.api.PDFWithPageNums;
 @Data
 @EqualsAndHashCode(callSuper = true)
 public class ManualRedactPdfRequest extends PDFWithPageNums {
-    @Schema(description = "A list of areas that should be redacted")
+    @Schema(
+            description = "A list of areas that should be redacted",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private List<RedactionArea> redactions;
 
-    @Schema(description = "Convert the redacted PDF to an image", defaultValue = "false")
-    private boolean convertPDFToImage;
+    @Schema(
+            description = "Convert the redacted PDF to an image",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean convertPDFToImage;
 
-    @Schema(description = "The color used to fully redact certain pages")
+    @Schema(
+            description = "The color used to fully redact certain pages",
+            defaultValue = "#000000",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String pageRedactionColor;
 }

src/main/java/stirling/software/SPDF/model/api/security/PDFPasswordRequest.java

@@ -13,6 +13,7 @@ public class PDFPasswordRequest extends PDFFile {
 
     @Schema(
             description = "The password of the PDF file",
-            requiredMode = Schema.RequiredMode.REQUIRED)
+            format = "password",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private String password;
 }

src/main/java/stirling/software/SPDF/model/api/security/RedactPdfRequest.java

@@ -13,22 +13,37 @@ public class RedactPdfRequest extends PDFFile {
 
     @Schema(
             description = "List of text to redact from the PDF",
-            type = "string",
+            defaultValue = "text,text2",
             requiredMode = Schema.RequiredMode.REQUIRED)
     private String listOfText;
 
-    @Schema(description = "Whether to use regex for the listOfText", defaultValue = "false")
-    private boolean useRegex;
+    @Schema(
+            description = "Whether to use regex for the listOfText",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean useRegex;
 
-    @Schema(description = "Whether to use whole word search", defaultValue = "false")
-    private boolean wholeWordSearch;
+    @Schema(
+            description = "Whether to use whole word search",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean wholeWordSearch;
 
-    @Schema(description = "Hexadecimal color code for redaction, e.g. #FF0000 or 000000", defaultValue = "#000000")
-    private String redactColor = "#000000";
+    @Schema(
+            description = "The color for redaction",
+            defaultValue = "#000000",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private String redactColor;
 
-    @Schema(description = "Custom padding for redaction", type = "number")
+    @Schema(
+            description = "Custom padding for redaction",
+            type = "number",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private float customPadding;
 
-    @Schema(description = "Convert the redacted PDF to an image", defaultValue = "false")
-    private boolean convertPDFToImage;
+    @Schema(
+            description = "Convert the redacted PDF to an image",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean convertPDFToImage;
 }

src/main/java/stirling/software/SPDF/model/api/security/RedactionArea.java

@@ -3,8 +3,10 @@ package stirling.software.SPDF.model.api.security;
 import io.swagger.v3.oas.annotations.media.Schema;
 
 import lombok.Data;
+import lombok.EqualsAndHashCode;
 
 @Data
+@EqualsAndHashCode
 public class RedactionArea {
     @Schema(description = "The left edge point of the area to be redacted.")
     private Double x;

src/main/java/stirling/software/SPDF/model/api/security/SanitizePdfRequest.java

@@ -11,21 +11,39 @@ import stirling.software.SPDF.model.api.PDFFile;
 @EqualsAndHashCode(callSuper = true)
 public class SanitizePdfRequest extends PDFFile {
 
-    @Schema(description = "Remove JavaScript actions from the PDF", defaultValue = "false")
-    private boolean removeJavaScript;
+    @Schema(
+            description = "Remove JavaScript actions from the PDF",
+            defaultValue = "true",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean removeJavaScript;
 
-    @Schema(description = "Remove embedded files from the PDF", defaultValue = "false")
-    private boolean removeEmbeddedFiles;
+    @Schema(
+            description = "Remove embedded files from the PDF",
+            defaultValue = "true",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean removeEmbeddedFiles;
 
-    @Schema(description = "Remove XMP metadata from the PDF", defaultValue = "false")
-    private boolean removeXMPMetadata;
+    @Schema(
+            description = "Remove XMP metadata from the PDF",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean removeXMPMetadata;
 
-    @Schema(description = "Remove document info metadata from the PDF", defaultValue = "false")
-    private boolean removeMetadata;
+    @Schema(
+            description = "Remove document info metadata from the PDF",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean removeMetadata;
 
-    @Schema(description = "Remove links from the PDF", defaultValue = "false")
-    private boolean removeLinks;
+    @Schema(
+            description = "Remove links from the PDF",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean removeLinks;
 
-    @Schema(description = "Remove fonts from the PDF", defaultValue = "false")
-    private boolean removeFonts;
+    @Schema(
+            description = "Remove fonts from the PDF",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private Boolean removeFonts;
 }

src/main/java/stirling/software/SPDF/model/api/security/SignPDFWithCertRequest.java

@@ -15,7 +15,8 @@ public class SignPDFWithCertRequest extends PDFFile {
 
     @Schema(
             description = "The type of the digital certificate",
-            allowableValues = {"PEM", "PKCS12", "JKS"})
+            allowableValues = {"PEM", "PKCS12", "JKS"},
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String certType;
 
     @Schema(
@@ -36,24 +37,31 @@ public class SignPDFWithCertRequest extends PDFFile {
     @Schema(description = "The password for the keystore or the private key", format = "password")
     private String password;
 
-    @Schema(description = "Whether to visually show the signature in the PDF file")
+    @Schema(
+            description = "Whether to visually show the signature in the PDF file",
+            defaultValue = "false",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private Boolean showSignature;
 
-    @Schema(description = "The reason for signing the PDF")
+    @Schema(description = "The reason for signing the PDF", defaultValue = "Signed by SPDF")
     private String reason;
 
-    @Schema(description = "The location where the PDF is signed")
+    @Schema(description = "The location where the PDF is signed", defaultValue = "SPDF")
     private String location;
 
-    @Schema(description = "The name of the signer")
+    @Schema(description = "The name of the signer", defaultValue = "SPDF")
     private String name;
 
     @Schema(
             description =
                     "The page number where the signature should be visible. This is required if"
-                            + " showSignature is set to true")
+                            + " showSignature is set to true",
+            defaultValue = "1")
     private Integer pageNumber;
 
-    @Schema(description = "Whether to visually show a signature logo along with the signature")
+    @Schema(
+            description = "Whether to visually show a signature logo along with the signature",
+            defaultValue = "true",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private Boolean showLogo;
 }

src/main/java/stirling/software/SPDF/model/api/security/SignatureValidationRequest.java

@@ -13,6 +13,8 @@ import stirling.software.SPDF.model.api.PDFFile;
 @EqualsAndHashCode(callSuper = true)
 public class SignatureValidationRequest extends PDFFile {
 
-    @Schema(description = "(Optional) file to compare PDF cert signatures against x.509 format")
+    @Schema(
+            description = "(Optional) file to compare PDF cert signatures against x.509 format",
+            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
     private MultipartFile certFile;
 }

src/main/java/stirling/software/SPDF/model/api/user/UpdateUserDetails.java

@@ -9,6 +9,9 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode(callSuper = true)
 public class UpdateUserDetails extends UpdateUserUsername {
 
-    @Schema(description = "new password for user")
+    @Schema(
+            description = "new password for user",
+            format = "password",
+            requiredMode = Schema.RequiredMode.REQUIRED)
     private String newPassword;
 }

src/main/java/stirling/software/SPDF/model/api/user/UpdateUserUsername.java

@@ -9,6 +9,6 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode(callSuper = true)
 public class UpdateUserUsername extends UsernameAndPass {
 
-    @Schema(description = "new password for user")
+    @Schema(description = "new username for user")
     private String newUsername;
 }

src/main/java/stirling/software/SPDF/model/api/user/Username.java

@@ -9,6 +9,6 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode
 public class Username {
 
-    @Schema(description = "username of user")
+    @Schema(description = "username of user", requiredMode = Schema.RequiredMode.REQUIRED)
     private String username;
 }

src/main/java/stirling/software/SPDF/model/api/user/UsernameAndPass.java

@@ -9,6 +9,6 @@ import lombok.EqualsAndHashCode;
 @EqualsAndHashCode(callSuper = true)
 public class UsernameAndPass extends Username {
 
-    @Schema(description = "password of user")
+    @Schema(description = "password of user", format = "password")
     private String password;
 }

src/main/java/stirling/software/SPDF/utils/PDFToFile.java

@@ -25,11 +25,13 @@ import com.vladsch.flexmark.util.data.MutableDataSet;
 
 import io.github.pixee.security.Filenames;
 
+import lombok.NoArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.SPDF.utils.ProcessExecutor.ProcessExecutorResult;
 
 @Slf4j
+@NoArgsConstructor
 public class PDFToFile {
 
     public ResponseEntity<byte[]> processPdfToMarkdown(MultipartFile inputFile)

src/main/resources/templates/misc/remove-blanks.html

@@ -21,12 +21,12 @@
                 <div th:replace="~{fragments/common :: fileSelector(name='fileInput', multipleInputsForSingleRequest=false, accept='application/pdf')}"></div>
                 <div class="mb-3">
                   <label for="threshold" th:text="#{removeBlanks.threshold}"></label>
-                  <input type="number" class="form-control" id="threshold" name="threshold" value="10">
+                  <input type="number" class="form-control" id="threshold" name="threshold" value="10" min="0" max="255" step="1">
                   <small id="thresholdHelp" class="form-text text-muted" th:text="#{removeBlanks.thresholdDesc}"></small>
                 </div>
                 <div class="mb-3">
                   <label for="whitePercent" th:text="#{removeBlanks.whitePercent}"></label>
-                  <input type="number" class="form-control" id="whitePercent" name="whitePercent" value="99.9" step="0.1">
+                  <input type="number" class="form-control" id="whitePercent" name="whitePercent" value="99.9" step="0.1" min="0.1" max="100">
                   <small id="whitePercentHelp" class="form-text text-muted" th:text="#{removeBlanks.whitePercentDesc}"></small>
                 </div>
                 <button type="submit" id="submitBtn" class="btn btn-primary" th:text="#{removeBlanks.submit}"></button>

testing/cucumber/features/examples.feature

@@ -2,7 +2,7 @@
 Feature: API Validation
 
   @positive @password
-  Scenario: Remove password 
+  Scenario: Remove password
     Given I generate a PDF file as "fileInput"
     And the pdf contains 3 pages
     And the pdf is encrypted with password "password123"
@@ -47,9 +47,9 @@ Feature: API Validation
     And the response file should have size greater than 100
     And the response PDF is passworded
 	And the response status code should be 200
-	
+
   @positive @password
-  Scenario: Add password with other params 
+  Scenario: Add password with other params
     Given I generate a PDF file as "fileInput"
     And the pdf contains 3 pages
     And the request data includes
@@ -64,7 +64,7 @@ Feature: API Validation
     And the response file should have size greater than 100
     And the response PDF is passworded
 	And the response status code should be 200
-	
+
   @positive @watermark
   Scenario: Add watermark
     Given I generate a PDF file as "fileInput"
@@ -78,6 +78,8 @@ Feature: API Validation
       | opacity       | 0.5              |
       | widthSpacer   | 50               |
       | heightSpacer  | 50               |
+      | alphabet      | roman            |
+      | customColor   | #d3d3d3        |
     When I send the API request to the endpoint "/api/v1/security/add-watermark"
     Then the response content type should be "application/pdf"
     And the response file should have size greater than 100
@@ -107,7 +109,7 @@ Feature: API Validation
     Then the response content type should be "application/pdf"
     And the response file should have size greater than 0
 	And the response status code should be 200
-	
+
   @positive @metadata
   Scenario: Update metadata
     Given I generate a PDF file as "fileInput"
@@ -127,4 +129,4 @@ Feature: API Validation
 	And the response PDF metadata should include "Title" as "Sample Title"
 	And the response status code should be 200
 
-  
+